The error-related negativity (ERN) has been called a putative neural marker of anxiety risk in children, with smaller ERN amplitudes denoting greater risk in early childhood. Children of anxious mothers are at elevated risk for anxiety problems compared to children of non-anxious mothers. Still unknown is whether discrete maternal symptoms interact with child ERN to predict different forms of child anxiety risk, knowledge of which could increase our understanding of the specificity of known conditions and pathways for transgenerational effects. Targeting two of the most prevalent forms of anxiety problems across children and adults, we tested whether maternal generalized anxiety disorder (GAD) and social phobia (SP) symptoms when children were 3 years old interacted with child ERN at age 4 years to predict child symptoms of overanxiousness and separation anxiety at age 5 years. We found that greater maternal SP, but not GAD, symptoms along with smaller (i.e., less negative) child ERN predicted more separation anxiety and overanxious symptoms in children, suggesting some specificity in prediction but less specificity in outcomes regarding the transmission of anxiety risk from mothers to offspring.